Soil Biopores and Non-Biopores Responses to Different Tillage Treatments in Sugarcane Fields in Guangxi, China

Abstract

Different types of soil macropores respond differently to various tillage practices, owing to disparities in origin, scale, morphology, and function, consequently exerting distinct effects on soil structure. This study aimed to investigate the response mechanisms of three different soil pore types (total macropores, non-biopores, and biopores) to two distinct tillage practices: smash-ridging tillage (T) and no-tillage (NT) in sugarcane fields. The parameters characterizing soil pore treatments in two and three dimensions were obtained using X-ray computed tomography scanning technology. ImageJ and MATLAB software were employed to analyze the data and separate soil macropores into biopores and non-biopores categories. The results showed that non-biopores predominated in two-dimensional cross-sectional areas in NT treatment, whereas biopores were more dominant in T treatment. Biopores in T treatment had a higher proportion of two-dimensional pores compared to NT treatment. A three-dimensional analysis indicated that total macropores had larger mean diameters (MD) and macroporosity, with more continuous tubular pores in T treatment than that in NT treatment. However, NT treatment had more numerous non-biopores with broader spatial distribution and complex morphology. Additionally, biopores in T treatment had larger MD and branching length density (LD). These vertically developed biopores, along with high macropore connectivity and under smash-ridging tillage, could improve soil water and pore conductivity. Therefore, smash-ridging tillage was more beneficial for sugarcane growth compared to no-tillage in Guangxi of China.